Linking motor imagery to motor execution

描述（由申请人提供）：运动意象是一个积极的认知过程，对人类运动表现有可测量的影响。运动意象所产生的潜在行为效应在最少的身体练习后就能表现出来。使用运动意象作为促进早期康复的潜在有效干预是有希望的，特别是当患者不能在早期开始物理康复时。越来越多的证据表明，想象的运动和实际的运动有着相似的神经基质，包括运动皮层。然而，在想象和执行的运动中，运动中心/通路之间的关系很少被研究。在本研究中，我们计划在正常受试者的运动想象中检查运动系统参与的特异性。基于我们之前的研究结果，我们假设在运动想象过程中，自主运动的运动中心/通路在阈下水平得到促进，并且这些以强制性的方式与相同动作的实际运动有明确的联系。具体目的是：1)利用反应时间范式分析运动想象过程中目标肌肉运动通路的运动特异性阈下激活；2)研究运动意象和运动执行之间的相互作用。在目的1中，我们将比较运动前时间（PMT）在休息时，在不同的背景想象运动，并在肌肉激活，以探讨运动意象的运动特异性效应。在反应时运动中，运动意象对PMT的影响可能表现为由于想象运动的原动机的皮质脊髓兴奋性增强而产生的兴奋效应和运动意象期间与任务复杂性增加相关的整体抑制作用的总和。皮质脊髓兴奋性的伴随变化将通过适当的时间经颅磁刺激（TMS）进一步研究。在目标2中，我们将通过比较经颅磁刺激的反应来研究运动想象过程中运动特异性阈下激活和实际运动过程中肌肉激活之间的相互作用。由于相互抑制的中央编程模式，我们预计预激活的手指屈肌对经颅磁刺激的反应将在想象的手指伸展期间减少，但在想象的手指弯曲期间可能不会进一步增加。

DESCRIPTION (provided by applicant): Motor imagery is an active cognitive process that has measurable effects on human motor performance. The latent behavioral effect resulting from motor imagery could be expressed after minimum physical practice. Using motor imagery as a potential efficient intervention to promote early recovery is promising particularly when patients could not start physical rehabilitation in an early stage. Accumulated evidence has demonstrated that imagined and actual movements share similar neural substrates, including the motor cortex. However, the relations between the motor centers/pathways during imagined and executed movements are rarely studied. In the proposed study, we plan to examine specificity of the involvement of the motor system during motor imagery in normal subjects. Based on our previous findings, we hypothesize that motor centers/ pathways for voluntary movements are facilitated at subthreshold levels during motor imagery and that these are specifically linked to actual movement of the same action in an obligatory manner. The specific Aims are: 1) to analyze movement-specific subthreshold activation of motor pathways of the target muscles during motor imagery using a reaction time paradigm; 2) to examine the interactions between motor imagery and motor execution. In Aim 1, we will compare the premotor time (PMT) at rest, during different background imagined movements, and during muscle activation to investigate the movement-specific effect of motor imagery. During reaction time movements, the effect of motor imagery on the PMT could appear as the sum of the excitatory effect due to enhanced corticospinal excitability specifically for the prime mover of the imagined movement and an overall inhibition associated with increased task complexity during motor imagery. The concomitant changes in the corticospinal excitability will be further investigated using appropriately timed transcranial magnetic stimulation (TMS). In Aim 2, we will examine the interactions between movement-specific subthreshold activation during motor imagery and muscle activation during actual movement by comparing the responses to TMS. Due to a centrally programmed pattern of reciprocal inhibition, we expect that the responses to TMS in the preactivated finger flexors will be decreased during imagined finger extension, but may not be further increased during imagined finger flexion.